Pressure vessels abound in modern usage for a myriad of different and diverse applications. Because of the possibility that upon a rupture, an overly-pressurized vessel may hurl metal fragments in many directions, much like shrapnel from a grenade, it is common to provide such vessels with pressure relief devices. In some applications, these pressure relif devices may be in the form of a mechanically-operable valve having a valve member biased to engage a seat. However, if the vessel is intended to store highly-pressurized fluid for a long period of time, the possibility of leakage past mechanical seals reduces the useable shelf or storage life of the vessel.
To overcome this deficiency, it has been known to provide such pressure vessels, particularly those which are designed for long-term storage, with diaphragm-type burst disks. These disks form an integral part of the enclosing wall, and, being hermetically sealed, effectively solve the problem of leakage past relatively-movable parts (e.g., between a valve member and its seat). In effect, such burst disks are a type of fuse which is deliberately designed to rupture in the event of an over-pressure condition within the vessel. However, such burst disks, while generally effective for their intended purpose, are believed to be unduly complicated to machine and manufacture, and are difficult to install. Moreover, the material of which the disk is made (e.g., stainless steel) will work-harden when the vessel is initially pressurized. Because of dimensional tolerances of the various components of such prior art burst disk assemblies, the expected burst pressure of a particular vessel would occur in a widened range.